THE ROLE OF IN-LINE INSPECTION IN THE MATERIAL VERIFICATION PROCESS. Simon Slater. IDT EXPO. Quarterly Meeting

Transcription

1 THE ROLE OF IN-LINE INSPECTION IN THE MATERIAL VERIFICATION PROCESS

2 INTRODUCTION A change in regulation is imminent Material properties will have to be Traceable, Verifiable and Complete Today I will talk about the advantages of using ILI as part of the material verification process and how it can augment the proposed process as set out in the regulations or be used to develop an alternative approach. Slide 2

3 WE CAN RECREATE HISTORY Slide 3

4 WE CAN SEE IT IN REAL LIFE Slide 4

5 BACK TO THE START Knowledge of material properties is critical to safe pipeline operation For new construction this is controlled by using components that are manufactured in line with rigorous specification requirements and retaining the records But what about the considerable amount of vintage pipelines we have? S. Nanney; Gas Transmission MAOP Verification Integrity Verification Process, OCC Pipeline Safety Conference, Slide 5

6 REGULATORY COMPLIANCE Related to material properties the Notice of Proposed Rule Making (NPRM) from PHMSA includes a new clause related to material verification, The exact content of clause is yet to be defined, however it is clear that operators will be required to deal with the issue of material verification for ongoing integrity management. Slide 6

7 DIGS AND MORE DIGS When the regulations are imposed, the first stage would be to look for records, which has most like already been done Once the operator has exhausted the search for records the NPRM calls for digs The challenge with digs is what approach is best opportunistic digs, equally spaced digs, or digs based on the best available information ILI technology is recognized as an option in the NPRM, so it can be used to augment the proposed NPRM process or as the basis for an operator defined approach Slide 7

8 DEALING WITH THREATS ILI is already used to deal with threats, using it to address the threat of unknown material properties is an obvious development. Slide 8

9 ILI AS PART MATERIAL VERIFICATION PROCESS ILI is a joint by joint inspection process Digs give detailed information on each joint but can only yield limited (in terms of quantity) data So we take the route of combining the two activities 1. ILI gives the first calculation of material properties 2. ILI data is the foundation to complete the verification process. Slide 9

10 MEASURING MATERIAL PROPERTIES USING ILI The ILI service is called RoMat PGS, which combines ILI and engineering assessment of the data Based on eddy current measurements with pre-magnetization of the pipe wall. Slide 10

11 MEASURING MATERIAL PROPERTIES USING ILI Sensor measurements depend on microstructure: o Microstructural phases o Grain size o Other factors such as dislocation density, segregation, inclusions, etc. Proprietary algorithms relate sensor readings to yield strength (YS) & ultimate tensile strength (UTS) Accuracy 80% confidence. Slide 11

12 WHAT THE ILI SERVICE GIVES US YS and UTS on a joint-by-joint basis for pipes and bends Populations - grouping of components with shared characteristics and properties (strength range, OD, WT, joint length, pipe/bend type) Grade Discrepancies/Outliers/Locations of interest Slide 12

13 PIPELINE DNA WITH ROMAT PGS Lets quickly walk through the ILI and data analysis process. Slide 13

14 FIRST CALCULATION OF PROPERTIES First we get YS and UTS on a joint-by-joint basis for pipes and bends without the need for any digs Slide 14

15 HIGH LEVEL POPULATIONS We can define Populations by wall thickness. Slide 15

16 UNCOVERING MORE DETAIL We can add joint length as a variable. Slide 16

17 CONSIDER PIPE TYPE We can use pipe type as a variable. Welded pipe Seamless Slide 17

18 USING STRENGTH AS A VARIABLE The tensile properties of a pipe population is described by a normal distribution. Slide 18

19 PICK OUT POPULATIONS Use the distributions of YS to define populations. Slide 19

20 THE RESULT Define all the populations and any outliers. Slide 20

21 ASSIGN A GRADE TO POPULATIONS Going back to the strength distributions, the grade is assigned to each population based on strength distribution. Slide 21

22 LIFE AFTER ILI Use ILI as a foundation to build on Digs are still required to verify the ILI and complete the material verification process The key is to make the most of your digs Slide 22

23 WHAT WE DO IN THE DITCH YS & UTS measurement using a nondestructive method Visual inspection Confirmation of weld type Microstructure (surface replication) Wall Thickness (by UT) Chemistry Hardness Destructive testing of cut-outs (if available) Slide 23

24 REGULATORY GUIDANCE FOR DIGS Use opportunistic digs Dig at equally spaced locations along a segment. Slide 24

25 OPPORTUNISTIC DIGS If you rely on opportunistic digs you may not be able to complete material verification You rely on lady luck If you dig on these 4 features reported by a crack detection tool, you only verify one population Slide 25

26 DIGS EQUALLY SPACED IN A SEGMENT If you rely on digs equally spaced you will duplicate effort and miss populations If we dig at locations at equal distances in this theoretical segment we would a) perform more digs in one population than you need b) miss populations Slide 26

27 THINGS CAN GET VERY DIFFICULT Equally spaced dig locations Multiplication of effort Missed Ollie Burkinshaw AIST RoMat PGS Presentation Sept 2018 Slide 27

28 TARGETED DIGS Leverage the best information available 1. First calculation of properties 2. Locations of specific interest (outliers/discrepancies) 3. Populations Leverage the fact that with each dig it is possible to expose two different populations as long as you know the weld at which the populations change. Slide 28

29 LESS DIGS TO GET INFORMATION REQUIRED Using the same example as before we can optimize the digs efforts by digging on a weld that has different populations either side. We now have 3 digs that can be used to verify all populations in this segment Slide 29

30 A SAFER APPROACH We can focus immediate attention on populations of interest. For example combination of lowest strength and lowest wall thickness Slide 30

31 SIGNIFICANT ADDED VALUE Added value of using ILI is the ability to correlate it with other threat specific ILI, such as corrosion or crack detection. Slide 31

32 DATA INTEGRATION We can make sure the right properties are being used to assess features. Slide 32

33 DATA INTEGRATION We can start to investigate why features are present in certain populations, is it a pipe issue? Is it location driven? What can be done to eliminate the threat? Slide 33

34 SUMMARY A change in regulation is imminent Material properties will have to be Traceable, Verifiable and Complete ILI can be used to augment the prescriptive NPRM process or can be used as the basis for a operator specific approach There is significant benefit in using ILI, which will get operators to the finishing line as quickly and safely as possible. Simon Slater Principal Integrity Engineer sslater@rosen-group.com Slide 34